Articulated work-holding jaw



May 29, 1956 w. G. WHEELER ET AL 2,747,544

ARTICULATED WORK-HOLDING JAW Filed Nov. l, 1952 5 Sheets-Sheet l i y l M ,(19

53 ZO/l WALTER G. WHEELER K//VGSL Y C. ORO/VE (ttorneg May 29, 1956' w. E. WHEELER ET AL 2,747,644

ARTICULATED WORK-HOLDING JAW Filed Nov. l. 1952 3 Sheets-Sheet 2 Snventors WALTER 6. WHEELER K/NGS/.EY C. DEO/VE Gttorneg United States Patent O ARTICULATED weas-notons@ 'JAW Walter G. Wheeler, Los Angeiesyand Kingsley C. Drone,

.Manhattan Beach, ACalif.,assignors to .lames H. -Kindelberger, Pacific Palisades, Calif.

ApplicationNovemberl, 1952', Serial No. '3-1`5,158'v 1-1' Claims. (Cl. 153-32) This invention relates to a jaw construction and, while having other uses, is particularly adapted for 'use as a sheet-'holding device, in machines that form sheets by bending and stretching the same over a die. Such stretch presses or stretch-forming machines areexemplified in pending' application, Serial No. 182,928, led September 2, 1950, and issued March 24, i953, as Patent No.

When a metall sheet is formed over a die of luniform `cylindricaily curved cross-section, about an axis perpendicular to the direction of pull, the opposed jaws lhat grip the oppositeend edges of the sheet are straight and require no articulation, because any cross-section perpendicular to the line of pull of the sheet is straight. The same is true if the die has a conical form. Consequently, under these conditions it is necessary only to so mount the opposite jaws that they can be voscillated in one plane 4and partiail'y rotated in the transverse plane while they vare being drawn apart and swung relative to the die during a stretch-forming operation. The abovementioned application shows jaws mounted in this manner.

in instances where the die is so formed that a sheet wrapped and stretched therearound is formed to have variously `curved cross-sectional forms, convex, concave, or both, that part of the sheet that takes the form vof the 'die will be properly Vformed while those portions of the sheet that extend from said formed part to the jaws will have diminishing curvature that terminates in straight edges where gripped in the jaws. All or most of these latter portions, not having the form of the die, represent Ventire length 'of vthe sheet between the jaws is formed 'substantially uniformly.

Accordingly, itis. an object of the present invention t providea'sheet-edge-gripping jaw that is capable of being articulated from a straight position to a variety of convexly and concavely curved positions, so that two such jaws gripping the .edges of a sheet being stretch-:formed 'can beadj'usted to conform to the shape of the die, thereby imparting to a formed sheet a desired curvature largely matching the die contours throughout its length between the jaws. By `means-of such jaws, waste islargely eliminated-or, at least, materially reduced and the stresses set up in the sheet-are also materially reduced because of the .uniformity of curvature thereof.

Theline of .pull of a vstraight jaw properly remains on .the center of thickness of a sheet being formed. How- .'ever, when 'the'jaws are adjusted to a sheet being formed Y`to have-afconvex curvature, or largely such a curvature, j 'fthe lines of pull of the jaws must be ladjusted .to Yobv'iate Cil any tendency for a bodily pivotal movement of the jaws in'aplane transverse to the lines of pull.

Another object of the invention, therefore, is to provide means to adjust the jaws relative to the lines of pull 'or tension so that said vlines of pull of the jaws are controllabl'e so as toproduce a desired bodily pivotal movement of the jaws on a pivot mounting the same.

Another object of the invention is to provide an articulated sheet-edge-gripping jaw that comprises a plurality .of hingedly lconnected jaw segments that bend the lsheet about thecenter of its thickness to compress one side of the Asheet and stretch `the opposite side without elongation of the sheet 'along said center of thickness.

A further object of the invention is to provide an articulated jaw of the character indicated in which the 'segments comprising the jaw are articulatory during bodily ymovement of the jaw relative to the die vor mandrel over which a sheet gripped by the jaw is formed, or movement of the die or mandrel relative to the jaw. In this manner, the form` imparted to the sheet by the mandrel can be imparted tothe jaw during the entire forming cycle.

A still further object of the invention is to provide an articulated jaw as above with adjustable stop means limiting the articulation of the jaw segments and with scale means associated with the stop means to recordand guide the adjustment of the latter.

A stll'further object of the invention is to provide an articulated jaw that is adapted to be placed underl'oad while in initial straight form and to place an .initially flat 'work sheet gripped thereby in tension and to maintain said tension on the sheet while the vjaw segments are pivoted relatively according to the curvature impartedit'o the work sheet byv the die around which said sheet is formed as the jaw is bodily moved.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements-of parts, which will more fully appear in the course ofthe following description. However, the drawings merely showY andv the following description merely describes embodiments of the present invention, which are given by way of illustration or example only.

v In the drawings, like reference characters designate similar parts in the several views.

Fig. 1, to a Ygreatly reduced scale, is a fragmentary plan view of one form .of stretch press and to which the present jaw is adapted to be applied.

Fig. 2 is an inner. edge elevational view of al1-articulated Yjaw according to the present invention.

Fig. 3 is an enlarged fragmentary View in the planeof Fig. 2, partly in cross-section, and showing the details of construction of the jaw.

Fig. 4 is a fragmentary plan sectional view astaken on line 4-4 of Fig. 3.

Fig. 5 is Va side elevational view, partly in section, of 'the jaw shownin Fig. 1, together with themeans mounting the same, the view being taken substantiallyon line 5 5 of Fig. 2.

Fig. 6 is a plan sectional view as taken on line 6-6 of Fig. 5.

Fig. 7 -is a similar but fragmentary view of amodiication.

Figs. 8, 9 and 150 are diagrammatic views of examples of '-adjusted positions of curvature of the jaw 'to 'impart similar curvatures to the end of a sheet gripped thereby.

With particular reference to Fig. yl, a die I5 and opposed -jaWs-16 cooperate to bend, while simultaneously stretching a sheet 17. Forming of the sheet results from movement of the jaws in the directions of arrows 18 and stretching by movement of said jaws in the directions of arrows 19. Substantially the same results are obtained by holding the jaws under tension, on fixed pivots that Yallow the same to rotate, and moving the die in the direction of arrow 20.

Reference is now made to Fig. in which it is shown that jaw 16 (comprised of all segments as a whole) is carried on a pivot 21 in'a clevis 22; that the clevis has Van axis of rotation 23, the same also being the axis on 'which jaw 16 is rotatable; that the jaw is oscillable on pivot 21; and that such oscillation is eiected through the medium of hydraulic cylinders 24 connected to arms V25 that areconnected to a block 26 on pivot 21. Thus, inVY addition to movement according to arrows 18 and 19,

the jaw 16 is rotatable on axis 23 and oscillable on the axis of pivot 21. The assemblage shown in Fig. l has one other movement-a bodily pivotal movement on a point orf the right end of Fig. 5. While the same may be shown in different structural form, all of thenforegoing, except the articulation of the jaws, is disclosed in ythe mentioned pending application Serial No. 182,928

and forms no part of the subject matter of the present invention.

` In addition to the articulated jaw 16, the present invention comprises means 27 to shift the clevis and the jaw to otset position relative to the axis 23 and, therefore, to the line of pull on arrow 19.

`of pivot pin 30 to pivot said segments relatively and,

thereby, articulate the jaw, and adjustable stop meansV 33, also on each side of the segments to limit the operation ofthe means 32 and the articulated adjustment of the segments of the jaw.

Each segment 28 and 29 comprises a body provided, above and below, with ears 34 that intert, as seen in Fig. 5, and are provided with in-line bores for pivot pins 30. In this manner, the body of each segment is provided, on each side of the center line that extends between the upper and lower ears thereof, with lateral lobes V35 that Vare reducingly tapered toward the opposite ends of said body, as best seen in Figs. 2 and 3. It will be clear, therefore, that the segments are capable of substantial relative pivotal movement on pins 30 before the angular faces 36 of adjacent segments can achieve contact. As shown, the segments are capable of about 20 of relative pivotal movement. By using at least iive segments 29 on each side of segment 28, the segments can be pivotally adjusted to bring the end segment to at least a 90 positionvrelative to segment 28 (see Fig. 8). Of

qcourse, any lesser relative pivotal adjustment of the segments can be Ymade as in Figs. 9 and 10 and the adjustments made in one direction or the other as in said latter figures. It follows thatany geometric form, within the limits of articulation of lthe segments, may be ef- ;fected and that said form may be made to conform substantially to the form of the mandrel as hereinbefore described.'

The gripperfmeans 31 is best seen in Fig. 6 and is provided in the outer end of each segment 28 and 29. As

Ashown, Vthe end of a sheet 17 is held gripped between clamp jaws 37 on gripper slides 38, guided by angularly disposed slideways 39. These elements are disposed in a longitudinal recess 40 formed in the outer end of each segment and are arranged as opposed pairs. In the form u illustrated, the angle of the slideways is such as to move clamp Vjaws-37V-Atoward each otherV when projected toward the open end of the recess and to separate the same when retracted. To eiect such projectionfand retraction of clamp jaws 37 there is provided in Veach segment an hydraulic device 5 comprising a cylinder 41a piston 42 in said cylinder and extending into recess 40, and a cap 43 at the projecting end of said piston and in operative engagement with gripper slides 38. It will be clear that by introducing hydraulic uid into one passage 44 the piston 42 is projected, and into the other passage 44 said piston is retracted. In the arrangement shown, while projection of piston 42 causes positive gripping of sheet 17, retraction of said piston retracts gripper slides 38 causing them to spread and release sheet 17.

15 In order that the edge of the sheet 17 may be uniformly introduced in the gripper means 31 of all of the segments, each pivot pin 30 is provided on the end thereof directed toward the sheet with a stop 45. to locate the sheet edge. f

2 The means 32 is best seen in Fig. 3. The same comprises a bore 46 in which is litted a sleeve 47 to comprise an hydraulic cylinder provided with pressure iluid by way of an inlet port 48, a piston 49 operable in said sleeve, and a connecting rod 50 extending between the 2 piston and the segment toward which the open end of bore 46 is directed. Said rod has a swivel connection 51 with the piston and a similar connection 52 with said adjacent segment. Said connections 51 and 52 permit connecting rod 50 to assume any angular disposition according to the mentioned angle of articulation of the segments on pivot pins 30.

A Since the pistons 49 are connected to the segments adjacent to the segments having bores 46 and cylinders 47, it will be clear that hydraulic uid introduced into said cylinders through ports 48 will act to separate the segment lobes 35 on that side of pivot pins 30 and bring together the lobes 35 on the opposite side, as illustrated in the lower portion of Fig. 3. Reverse pivotal movement of the segments is eiected by introduction of hydraulic fluid into the cylinders on said opposite side of the segments. Of course, when the cylinder in one lobe is being supplied with uid, the cylinder in the opposite lobe is permitted to exhaust the fluid therein. The stop means 33 is also best seen in Fig. 3 and, as shown in Fig. 2, each segment is provided with such means on both lobes 35 thereof to limit, according to its adjustment, the degree of pivotal movement of the different segments, relatively. Each stop means 33 Vis shown as comprising an integral lug 53 on the end of lobe 35, a threaded through bore 54 in said lug, an adjusting screw 55 threadedly engaged in said bore, a tiltable end 56 on that end of screw 55 that is directed toward an abutment face 57 provided on the adjacent segment, an index pin 58 on the opposite face of the lug, and a'scale 59 provided on a tlat formed on said screw and readable in connection with said index pin. The scale 59 may be graduated to read in degrees of angle between adjacent segments. Accordingly, by adjusting said screw according to the degree of pivot desired of any two adjacent segments, the tiltable end 56 will achieve abutment with face 57 when said angle has been attained.

It will be evident from the foregoing, starting with ya at sheet gripped between two jaws 16 0n yboth sides of a mandrel 15, that as the jaws are moved, as suggested in Fig. l, to form the sheet around said mandrel, as the lsheet takes on the form imparted by said mandrel, the iiuid to the various means 32 is controlled to eiect articulation of the jaws accordingly.Y Thus, when the Abending operation is completed, the sheet has substantially the same form at its ends as at the'portion thereof that is engaged with the mandrel. After removing the formed sheet from the jaws, by directing the pressure to the opposing cylinders of means 32, a new tlat sheet can be V#thickness yof the sheet. bend, vwill contract, while Ythe outsidel will V:stretch-accord- :tartar-,B44

inserted into fthe jaws because the :segments #are #readily ilarticulated to r effect "such insertion.

"Sincetthose iportions -of the sheet 'that :are fdisposed @between-thev segments are not gripped-nor are they'trained 4over any bendingiformythe sheet-isnot-elongated because :fthe-:bends ,Yat-these points vtake place'on'fthefmiddle-o'f the The sheetfon :the inside of such .-.of segment 2S are adjusted to positions on the same side, -.as shown in Fig. 8, and pull is exerted on the sheet, there will be setup a rotational force that .will produce a bodily .pivotaLmovement about the -mentioned point of ..the .right end of Fig. 5. Only when the segments 29, `on-both V`ven,ds,.are adjusted oppositely, .as in Eig. 10, Will thepull on.axis23.remain normal. As shown-by Figs..8-and 9, itis preferred to shift the jaw 16, when the adjustment of the segments 29 is on the same side, so that the center of pull on axis 23 is oiset from segment 28 and between the same and the endmost segments 29. The means 27 is provided for this purpose.

Referring particularly to Figs. 2, 5 and 6, the means 27 comprises a laterally extending yoke 60 ailixed to one side of clevis 22, a piston stem 61 fixedly carried by said yoke and having a piston 62 on the end thereof, an hydraulic cylinder 63 for said piston extending transversely through and clear of said clevis rearward of segment 28, and opposed lobes 64 on said cylinder and in sliding engagement in guideways 65 formed in the clevis.

It will be seen from the foregoing that introduction of hydraulic uid into one end of cylinder 63 will result in lateral movement in one direction of clevis 22 and jaw 16 thereon. introduction of such fluid in the opposite end of said cylinder will result in such lateral movement in the opposite direction. Thus, the clevis and jaw may be laterally adjusted in either direction relative to extension 66 formed on cylinder 63 and constituting the means by which the jaw is mounted in operative position.

Fig. 7 shows a modication of the above-described hydraulic shifting means. A nut 67 is held by a fitting 68 against movement relative to clevis 22, and a screw 69, rotated by a handle 70, is engaged with said nut and is rotationally carried by extension 71, the counterpart of extension 66. lt will be clear that the handle may be rotated to effect offset adjustment of clevis 22 as desired in substantially the same way as in the earlier described form.

It is to be understood that the means 27 may be operated during the stretch-forming operation to vary the degree of olset of pull on axis 23 as the flat sheet is changed in form by the mandrel.

Various sca.es may be applied to the device to guide the adjustment of the parts. Scale 59 has already been described. A sector scale 72, on one side of clevis 22, may be read in connection with an index arm 73 aliixed to an end of pivot pin 21 to show the degree of tilt of jaw 16 on said pivot pin. A scale 74, carried by extension 66, may be used to show the amount of offset of the clevis relative to extension 66 or extension 71, as the case may be.

While the invention that has been illustrated and described is now regarded as the preferred embodiments, the construction is, of course, subject to modication without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular forms of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what we claim and desire to secure by Letters Patent is:

il. FAL-jawadaptedftorgripeoneend-of atshe'etwliile being --lwrappedrarounda die during relative movement 'ofthe jaw and die, said Ljaw comprising-a plurality off-clamps,

hinges v-connecting the-clamps '.in-'seriessand inV parallel -relationship,-theraxes of said hinges.extendingi-towardthe work-receiving'ends of the clamps,'and 'means-within' the Iclamps on-both sides ofthe hinges'to Vangulaily -adjust the clamps-relatively. Y

2. SA jaw adapted-to grip one end of a sheetwhile being wrapped around a die lduring v relative .movement of` the Vjaw and die, Ysaidjaw comprising a plurality of clamps, =hinges .connecting lthe clamps in series and in kparallel relationship, the axes of said hinges'extendingtoward 'ithewvork-receiving ends ofthe clamps,.and means Awithin the clamps on both sides of the hingeslto angularly adjust the clamps relatively, and.stopmeans on'bothsidesof the pivots to limit said angular. adjustment.

3. -A jawfadapted-to grip-.one end of-a sheet whileibeing wrapped around'a Vdie .during relative movement of -the jaw. and die,:said jaw being mounted to -pivot Abodily ,-in Va plane transverse tothe sheet which. it,grips and oscillate bodily in the plane of said sheet, said jaw comprising a plurality of clamps, a plurality of hinges connecting the clamps in series and in parallel relationship, the axes of said hinges extending toward the work-receiving ends of the clamps whereby the clamps are adapted to be articulated, and means to shift the jaw bodily to adjusted positions parallel to the plane of the sheet.

4. A jaw structure comprising a clevis, an articulated clamping mechanism carried by said clevis on a transverse pivot and adapted to grip the end of a sheet, a transverse slide support for the clevis, and means to move the clevis on its support.

5. A sheet-end-gripping jaw comprising a clamping element, two groups of clamping mechanisms arranged on both sides of the clamping element, each said mechanism comprising a plurality of clamps, parallel pivots connecting the clamping element to the clamping mechanisms and the clamps of said mechanisms one to the other, said clamping element and each clamp being reducingly tapered from the middle thereof to both ends, and means within said clamping element and clamps on both sides of the mentioned pivots to pivotally move each said clamp on its pivot relative to an adjacent clamp, the axes of said pivots extending toward the work-receiving ends of the clamps.

6. A sheet-end-gripping jaw according to claim 5, means on the reduced ends of the clamps to limit the pivotal movement of said clamps.

7. In a worl -clamping jaw, the combination comprisino a clamping mechanism having a plurality of clamps, a plurality of pivots connecting the medial portions of said clamps in series and in parallel relationship, the axes of said pivots extending toward the work-receiving ends of the clamps, and means interconnecting the clamps on both sides of said pivots to pivotally move one clamp relative to the other.

8. ln a work-clamping jaw, the combination comprising a clamping mechanism having a plurality of clamps, a plurality of pivots connecting the medial portions of said clamps in series and in parallel relationship, the axes of said pivots extending toward the work-receiving ends of the clamps, means interconnecting the clamps on both sides of said pivots t-o pivotally move one clamp relative to the other, and means on both sides of the pivots to limit said pivotal movement.

9. In a work-gripping jaw, the combination comprising a clamping mechanism having a plurality of clamps, a plurality of pivots connecting the medial portions of said clamps in series and in parallel relationship, the axes of said pivots extending toward the work receiving ends of the clamps, means interconnecting the clamps on both sides of said pivots to pivotally move one clamp relative to the other, each said means comprising a cylinder in one clamp adapted to receive hydraulic duid, a piston in said cylinder and projectable by said uid in a` direction Vtoward the other clamp, and a connecting rod interconnecting said piston and said other clamp.

10. VIn'a Work-gripping jaw, the combination compris- Ving a clamping mechanism having a plurality of clamps,

.ay plurality of pivots connecting the medial portions of said clamps in series and in parallel relationship, the axes of said pivots extending toward the work receiving ends Aof the clamps, means interconnecting the clamps on both sides of said pivots to pivotallymove one clamp relative to the other, each said means comprising a cylinder in Vone clamp adapted to receive hydraulic uid, a piston in said cylinder and projectable by said iluid in a direction toward the other clamp, and a connecting rod interconnecting said piston and said other clamp, said connecting rod being provided with a swivel to connect to the piston and to said other clamp.

Y 1l. vIn a work-gripping jaw, the combination comprising a clamping mechanism having a plurality of clamps,

a plurality of pivots connecting the medial portions of said clamps in series and in parallel relationship, the

axes of said pivots'extending toward'the Work receiving ends of the clamps, means'interconnectng the .clamps 'on both sides of said pivots to pivotally move one clamp relative to the other, each clamp being provided with-'a kpair of lwork-end-grippirig jaw elements and said pairs of Velementsbeing aligned on the pivot and spaced from eachother slo that the portion of the work between the .pairs of elements is ungripped and bendable during said ypivotal movement of the clamps to contract on one sideandV correspondingly expand on the/other.

v References Cited in the file of this patent UNITED STATES PATENTS King Oct. 24, 1865 

